Figure 2.

A long distance between the BP and 3′ SS inhibits the second step of splicing. (A) Intronic sequences of TER1 constructs used in B and C. Splice sites and BSs are in capital letters for emphasis. Inserted adenosines are underlined. (B) Northern blot analysis for ter1 constructs expressed from plasmids under the control of the ter1 promoter. RNaseH cleavage was used to improve resolution of precursor, spliced, and cleaved forms. The cleaved form was quantified relative to loading control snRNA101 (LC) and normalized to wild-type levels. The data are represented as mean ± SEM, with n = 2 for “9+3A” construct and n = 3 for all other constructs. An arrow points to the cleaved form. (C) RT–PCR across the TER1 intron to visualize the relative abundance of precursor and spliced forms.